A battery pack is a set of any number of (preferably) identical batteriesor individual battery cells. They may be configured in a series, parallel or a mixture of both to deliver the desired voltage, capacity, or power density. The term battery pack is often used in reference to RC hobby toys and battery electric vehicles.

Components of battery packs include the individual batteries or cells, and the interconnects which provide electrical conductivity between them. Rechargeable battery packs often contain a temperature sensor, which the battery charger uses to detect the end of charging. Interconnects are also found in batteries as they are the part which connects each cell, though batteries are most often only arranged in series strings.

When wiring a pack in parallel there are various methods and one should take into consideration the balance of the electrical circuit. Battery regulators are sometimes used to keep the peak voltage of each individual battery or cell below its maximum value so to allow weaker batteries to be fully charged, bringing the whole pack back into balance. Active balancing can also be performed by battery balancerdevices which can shuttle energy from strong batteries to weaker ones in real time for even better balance. A well-balanced pack lasts longer and delivers better performance so it is a rather beneficial component of high capacity or expensive packs.

For an inline package, cells are selected and stacked with solder in between them. The cells are pressed together and a current pulse generates heat to solder them together and to weld all connections internal to the cell.